Patients included in randomised controlled trials do not represent those seen in clinical practice: focus on antimicrobial agents

Racial and Ethnic Disparities in Antihypertensive Medication Prescribing Patterns and Effectiveness

Variability in drug effectiveness and provider prescribing patterns have been reported in different racial and ethnic populations. We sought to evaluate antihypertensive drug effectiveness and prescribing patterns among self-identified Hispanic/Latino (Hispanic), Non-Hispanic Black (Black), and Non-Hispanic White (White) populations that enrolled in the NIH All of Us Research Program, a US longitudinal cohort. We employed a self-controlled case study method using electronic health record and survey data from 17,718 White, Hispanic, and Black participants who were diagnosed with essential hypertension and prescribed at least one of 19 commonly used antihypertensive medications. Effectiveness was determined by calculating the reduction in systolic blood pressure measurements after 28 or more days of drug exposure. Starting systolic blood pressure and effectiveness for each medication were compared for self-reported Black, Hispanic, and White participants using adjusted linear regressions. Black and Hispanic participants were started on antihypertensive medications at significantly higher SBP than White participants in 13 and 7 out of 19 medications, respectively. More Black participants were prescribed multiple antihypertensive medications (58.46%) than White (52.35%) or Hispanic (49.9%) participants. First-line HTN medications differed by race and ethnicity. Following the 2017 American College of Cardiology and the American Heart Association High Blood Pressure Guideline release, around 64% of Black participants were prescribed a recommended first-line antihypertensive drug compared with 76% of White and 82% of Hispanic participants. Effect sizes suggested that most antihypertensive drugs were less effective in Hispanic and Black, compared with White, participants, and statistical significance was reached in 6 out of 19 drugs. These results indicate that Black and Hispanic populations may benefit from earlier intervention and screening and highlight the potential benefits of personalizing first-line medications.

Are we enrolling the right patients? A scoping review of external validity and generalizability of clinical trials in bloodstream infections

BACKGROUND

Having a representative population in randomized clinical trials (RCTs) improves external validity and generalizability of trial results. There are limited data examining differences between RCT-enrolled and real-world populations in bloodstream infections (BSI).

OBJECTIVES

We conducted a scoping review aiming to review studies assessing generalizability of BSI RCT populations, to identify sub-groups that have been systematically under-represented and to explore approaches to improve external validity of future RCTs.

SOURCES

MEDLINE, Embase, and Cochrane Library databases were searched for terms related to external validity or generalizability, BSI, and clinical trials in papers published up to 1 August 2023. Studies comparing enrolled versus nonenrolled patients, or papers discussing external validity or generalizability in the context of BSI RCTs were included.

CONTENT

Sixteen papers were included in the final review. Five compared RCT-enrolled and nonenrolled participants from the same source population. There were significant differences between the two groups in all studies, with nonenrolled patients having a greater comorbidity burden and consistently worse outcomes including mortality. We identified several barriers to improving generalizability of RCT populations and outlined potential approaches to reduce these barriers, such as alternative/simplified consent processes, streamlining eligibility criteria and follow-up procedures, quota-based sampling techniques, and ensuring diversity in site and study team selection.

IMPLICATIONS

Study cohorts in BSI RCTs are not representative of the general BSI patient population. As we increasingly adopt large pragmatic trials in infectious diseases, it is important to recognize the importance of maximizing generalizability to ensure that our research findings are of direct relevance to our patients.

Infrastructure challenges to doing health research "where populations with the most disease live" in Covid times-a response to Rai et al. (2021)

Background

The failure of randomised controlled trials to adequately reflect areas of highest health need have been repeatedly highlighted. This has implications for the validity and generalisability of findings, for equity and efficiency, but also for research capacity-building. Rai et al. (BMC Med Res Methodol 21:80, 2021) recently argued that the poor alignment between UK clinical research activity (specifically multi-centre RCTs) and local prevalence of disease was, in part, the outcome of behaviour and decision-making by Chief Investigators involved in trial research. They argued that a shift in research culture was needed. Following our recent multi-site mixed methods evaluative study about NHS 111 online we identify some of the additional structural barriers to delivering health research “where populations with the most disease live”, accounting for the Covid-19 disruption to processes and delivery.

Methods

The NHS 111 study used a mixed-method research design, including interviews with healthcare staff and stakeholders within the primary, urgent and emergency health care system, and a survey of users and potential users of the NHS 111 online service. This paper draws on data collated by the research team during site identification and selection, as we followed an action research cycle of planning, action, observation and reflection. The process results were discussed among the authors, and grouped into the two themes presented.

Results

We approached 22 primary and secondary care sites across England, successfully recruiting half of these. Time from initial approach to first participant recruitment in successful sites ranged from one to ten months. This paper describes frontline bureaucratic barriers to research delivery and recruitment in the local Clinical Research Network system and secondary care sites carrying large research portfolios, alongside the adaptive practices of research practitioners that mitigate these.

Conclusions

This paper augments the recommendations of Rai et al., describing delays encountered during the COVID-19 pandemic, and suggesting in addition to cultural change, it may be additionally important to dismantle infrastructural barriers and improve support to research teams so they can conduct health research “where populations with the most disease live”.

Inadequate reporting of participants eligible for randomized controlled trials - A systematic review and meta-analysis

OBJECTIVE

to characterize randomized controlled trials (RCTs) that did not report the overall number of participants assessed for eligibility and to identify factors associated with higher enrollment rates.

STUDY DESIGN AND SETTING

Systematic review and meta-analysis of RCTs in several pre-defined fields in internal medicine. We randomly extracted 360 articles that were published in 2017. Trials that reported numbers of assessed for eligibility patients were compared with those who did not. Recruitment rates were calculated in order to investigate whether they were associated with trial characteristics.

RESULTS

A total of 360 RCTs were included. Only 2-thirds of the trials (242/360) reported the number of patients assessed for eligibility. Trials reporting eligibility data had better methodology, reported on the tested hypothesis, included a placebo arm, evaluated soft outcomes, published their findings in higher impact journals and recruited a higher number of randomized patients than those who did not. Recruitment rates in 225 (62.5%) trials enabling their calculation, were significantly higher in trials sponsored by industry, conducted in multiple centers and countries, including inpatients, tested non-inferiority hypothesis, included a placebo arm, and evaluated surrogate outcomes.

CONCLUSIONS

Reporting of participant eligibility continues to be scarce. Inadequate reporting was associated with poor methodological characteristics in trials.

Shifting research culture to address the mismatch between where trials recruit and where populations with the most disease live: a qualitative study

Background

Research participation is beneficial to patients, clinicians and healthcare services. There is currently poor alignment between UK clinical research activity and local prevalence of disease. The National Institute of Health Research is keen to encourage chief investigators (CIs) to base their research activity in areas of high patient need, to support equity, efficiency and capacity building. We explored how CIs choose sites for their trials and suggest ways to encourage them to recruit from areas with the heaviest burden of disease.

Methods

Qualitative, semi-structured telephone interviews with a purposive sample of 30 CIs of ongoing or recently completed multi-centre trials, all of which were funded by the UK National Institute of Health Research.

Results

CIs want to deliver world-class trials to time and budget. Approaching newer, less research-active sites appears risky, potentially compromising trial success. CIs fear that funders may close the trial if recruitment (or retention) is low, with potential damage to their research reputation.

We consider what might support a shift in CI behaviour. The availability of ‘heat maps’ showing the disparity between disease prevalence and current research activity will help to inform site selection. Embedded qualitative research during trial set up and early, appropriate patient and public involvement and engagement can provide useful insights for a more nuanced and inclusive approach to recruitment. Public sector funders could request more granularity in recruitment reports and incentivise research activity in areas of greater patient need. Accounts from the few CIs who had ‘broken the mould’ suggest that nurturing new sites can be very successful in terms of efficient recruitment and retention.

Conclusion

While improvements in equity and capacity building certainly matter to CIs, most are primarily motivated by their commitment to delivering successful trials. Highlighting the benefits to trial delivery is therefore likely to be the best way to encourage CIs to focus their research activity in areas of greatest need.

Supplementary Information

The online version contains supplementary material available at 10.1186/s12874-021-01268-z.

Using external data to assess the external validity of a randomised controlled trial

BACKGROUND

Few studies have addressed external validity of randomized controlled trials in infectious diseases. We aimed to assess the external validity of an investigator-initiated trial on treatment for uncomplicated urinary tract infection.

METHODS

In the original study, women (n = 513) with urinary tract infection were randomized to nitrofurantoin or fosfomycin treatment in three countries between 2013 and 2017. In the present study we compared women who were screened for enrolment but excluded to women who participated in the trial, both groups in Israel. The primary outcome was the rate of emergency department index visits resulting in hospitalization within 28 days.

RESULTS

We compared 127 included to 110 excluded patients. The most common reasons for exclusion were logistic difficulties in recruitment and antibiotic use in the preceding month. Included patients tended to be older [39 (IQR 29-59) vs. 35.5 (IQR 24-56.25 years)], more likely to have history of recurrent infection and had more urinary symptoms. Among excluded patients, 13.6% (15/110) had initial visits resulting in hospitalization compared to 3.1% (4/127) of included participants (p = .003). The rate of emergency department visits within 28 days was similar in both groups. Clinical and microbiological failures were significantly more common in included patients [26% (33/127) vs. 1.8% (2/110), p < .001; 7.9% (10/127) vs. 0% (0/110), p = .003; respectively].

CONCLUSIONS

While differences were observed between included and excluded patients, the excluded group did not represent a more 'complicated' population. The present study shows the importance of collecting data on patients excluded from randomized controlled trials.

Rapidly Improving ARDS in Therapeutic Randomized Controlled Trials

BACKGROUND

Observational studies suggest that some patients meeting criteria for ARDS no longer fulfill the oxygenation criterion early in the course of their illness. This subphenotype of rapidly improving ARDS has not been well characterized. We attempted to assess the prevalence, characteristics, and outcomes of rapidly improving ARDS and to identify which variables are useful to predict it.

METHODS

A secondary analysis was performed of patient level data from six ARDS Network randomized controlled trials. We defined rapidly improving ARDS, contrasted with ARDS > 1 day, as extubation or a Pao₂ to Fio₂ ratio (Pao₂:Fio₂) > 300 on the first study day following enrollment.

RESULTS

The prevalence of rapidly improving ARDS was 10.5% (458 of 4,361 patients) and increased over time. Of the 1,909 patients enrolled in the three most recently published trials, 197 (10.3%) were extubated on the first study day, and 265 (13.9%) in total had rapidly improving ARDS. Patients with rapidly improving ARDS had lower baseline severity of illness and lower 60-day mortality (10.2% vs 26.3%; P < .0001) than ARDS > 1 day. Pao₂:Fio₂ at screening, change in Pao₂:Fio₂ from screening to enrollment, use of vasopressor agents, Fio₂ at enrollment, and serum bilirubin levels were useful predictive variables.

CONCLUSIONS

Rapidly improving ARDS, mostly defined by early extubation, is an increasingly prevalent and distinct subphenotype, associated with better outcomes than ARDS > 1 day. Enrollment of patients with rapidly improving ARDS may negatively affect the prognostic enrichment and contribute to the failure of therapeutic trials.

Clinical drug trials in general practice: how well are external validity issues reported?

BACKGROUND

When reading a report of a clinical trial, it should be possible to judge whether the results are relevant for your patients. Issues affecting the external validity or generalizability of a trial should therefore be reported. Our aim was to determine whether articles with published results from a complete cohort of drug trials conducted entirely or partly in general practice reported sufficient information about the trials to consider the external validity.

METHODS

A cohort of 196 drug trials in Norwegian general practice was previously identified from the Norwegian Medicines Agency archive with year of application for approval 1998-2007. After comprehensive literature searches, 134 journal articles reporting results published from 2000 to 2015 were identified. In these articles, we considered the reporting of the following issues relevant for external validity: reporting of the clinical setting; selection of patients before inclusion in a trial; reporting of patients' co-morbidity, co-medication or ethnicity; choice of primary outcome; and reporting of adverse events.

RESULTS

Of these 134 articles, only 30 (22%) reported the clinical setting of the trial. The number of patients screened before enrolment was reported in 61 articles (46%). The primary outcome of the trial was a surrogate outcome for 60 trials (45%), a clinical outcome for 39 (29%) and a patient-reported outcome for 25 (19%). Clinical details of adverse events were reported in 124 (93%) articles. Co-morbidity of included participants was reported in 54 trials (40%), co-medication in 27 (20%) and race/ethnicity in 78 (58%).

CONCLUSIONS

The clinical setting of the trials, the selection of patients before enrolment, and co-morbidity or co-medication of participants was most commonly not reported, limiting the possibility to consider the generalizability of a trial. It may therefore be difficult for readers to judge whether drug trial results are applicable to clinical decision-making in general practice or when developing clinical guidelines.

Bloodstream infections in older patients

Bloodstream infections (BSIs) are both common and fatal in older patients. We describe data from studies evaluating older patients hospitalized with BSIs. Most older patients with BSIs present "typically" with either fever or leukocytosis. The most common source of BSI in older patients is the urinary tract, and accordingly, Gram-negative organisms predominate. A significant part of these BSIs may thus be preventable by removal of unnecessary urinary catheters. Increased long term mortality is reported following BSIs in older patients, however, data on other long-term outcomes, including functional capacity, cognitive decline and others are lacking. Management of BSIs may include less invasive procedures due to the fragility of older patients. This approach may delay the diagnosis and treatment in some cases. Older patients are probably under-represented in clinical trials assessing treatment of bacteremia. Physicians treating older patients should consider the relevance of these studies' outcomes.

Evaluating the Generalisability of Trial Results: Introducing a Centre- and Trial-Level Generalisability Index

BACKGROUND

Few randomised controlled trials (RCTs) recruit centres representatively, which may limit the external validity of trial results.

OBJECTIVE

The aim of this study was to propose a proof-of-concept method of assessing the generalisability of the clinical and cost-effectiveness findings of a given RCT.

METHODS

We developed a generalisability index (Gix), informed by centre-level characteristics, as a measure of centre and trial representativeness. The centre-level Gix quantifies how representative a centre is in relation to its jurisdiction, e.g. a country or health authority. The trial-level Gix quantifies how representative trial recruitment is in relation to clinical practice in the jurisdiction. Taking a real-world RCT as a case study and assuming trial-wide results to represent 'true jurisdiction values', we used simulation methods to recreate 5000 RCTs and investigate the relationship between trial representativeness, reflected by the standardised trial-Gix, and the deviation of simulated trial results from the 'true values'.

RESULTS

The simulation study provides evidence that trial results (odds ratio for the primary outcome and incremental quality-adjusted life-years) were influenced by the representativeness of the sample of recruiting centres. Simulated RCTs with the closest results to the 'true values' were those whose recruitment closely mirrored the jurisdiction-wide context. Results appeared robust to six alternative specifications of the Gix.

CONCLUSIONS

Our findings suggest that an unrepresentative selection of centres limits the external validity of trial results. The Gix may be a valuable tool to help facilitate rational selection of trial centres and ensure the generalisability of results at the jurisdiction level.

External validity of a randomised controlled trial on the treatment of severe infections caused by MRSA

OBJECTIVES

To assess the external validity of a pragmatic, investigator-initiated RCT on treatment of severe infections caused by methicillin-resistant Staphylococcus aureus (MRSA), we compared patient characteristics and treatment effect estimates for patients included in the RCT versus those excluded.

PARTICIPANTS AND OUTCOMES

The RCT included hospitalised patients with documented or highly-probable invasive MRSA infections who were randomised to vancomycin versus trimethoprim-sulfamethoxazole (TMP-SMX) treatment, between 2007 and 2014. A concomitant observational study prospectively included all consecutive patients, between 2008 and 2011, who were excluded from the RCT due to no consent, meningitis, left-sided endocarditis, severe neutropaenia, chronic renal dialysis or treatment with study medications for longer than 48 h. The primary outcomes were clinical failure at day 7 and 30-day mortality for both studies. We compared baseline and infection characteristics, outcome rates and treatment effect estimates for included versus excluded patients.

RESULTS

The RCT included 252 patients who were compared with 220 excluded patients who were observed. Inability to provide informed consent was the main reason for patient exclusion. Excluded patients' functional and cognitive performance was significantly poorer than that of included patients. Sepsis was more severe among excluded patients (higher rates of mechanical ventilation, indwelling catheters, septic shock and organ failure). Clinical failure occurred in 83/252 (32.9%) versus 175/220 (79.5%) and deaths in 32 (12.7%) versus 64 (29.1%) for included versus excluded patients, p<0.001 for both comparisons. Comparing vancomycin to TMP-SMX, in the RCT mortality, was non-significantly lower with vancomycin (OR 0.76, 95% CIs 0.36 to 1.62), while in the observational analysis of excluded patients, mortality was significantly higher with vancomycin (OR 2.63, 1.04 to 6.65), p=0.04 for the difference.

CONCLUSIONS

Patient characteristics, outcome event rates and treatment effects differed significantly in the setting of a RCT, despite its pragmatic design, compared to patients treated outside the trial settings.

Participation of elderly adults in randomized controlled trials addressing antibiotic treatment of pneumonia

OBJECTIVES

To examine how relevant current evidence on antibiotic treatment of pneumonia is for elderly adults.

DESIGN

Systematic review.

SETTING

Randomized controlled trials (RCTs; N = 43) comparing different antibiotics and prospective observational studies (N = 182) published since 2005.

PARTICIPANTS

Adults with community-acquired (CAP), healthcare-associated (HCAP), hospital-acquired (HAP), or ventilator-associated (VAP) pneumonia.

MEASUREMENTS

Exclusion criteria that could preferentially limit participation of elderly adults were examined, subgroup or other adjusted analyses were searched for according to age, and treatment effects in participants younger than 65 in RCTs were compared with those in participants aged 65 and older. Mean participant ages in RCTs and observational studies were compared. Risk ratios (RRs) with 95% confidence intervals (CIs) for differences between older and younger adults were pooled using a fixed effect metaanalysis.

RESULTS

No RCT reported exclusion based on an upper age limit; 100% of community CAP trials, 90% of hospitalized CAP trials, and 76% of HAP and VAP trials excluded individuals based on comorbidities. None of the RCTs reported a subgroup analysis for mortality according to age. The RR for the pooled difference in treatment failure rates between participants younger than 65 and those aged 65 and older was 1.25 (95% CI = 0.94-1.65, 12 RCTs) and between participants younger than 75 and aged 75 and older was 1.43 (95% CI = 0.98-2.09, 7 RCTs). RCT participants were significantly younger (54.0 ± 9.6) than those in observational studies of CAP (66.2 ± 8.1, P < .001). Age differences were not significant for HCAP, HAP, and VAP.

CONCLUSION

Elderly adults are often excluded from RCTs of bacterial pneumonia. No data were found on the comparative efficacy of antibiotic treatment in elderly adults and the general population.

Compliance with once-daily versus twice or thrice-daily administration of antibiotic regimens: a meta-analysis of randomized controlled trials

Objective

To investigate whether compliance of patients to antibiotic treatment is better when antibiotics are administered once than multiple times daily.

Methods

We performed a systematic search in PubMed and Scopus databases. Only randomized controlled trials were considered eligible for inclusion. Compliance to antibiotic treatment was the outcome of the meta-analysis.

Results

Twenty-six studies including 8246 patients with upper respiratory tract infections in the vast majority met the inclusion criteria. In total, higher compliance was found among patients treated with once-daily treatment than those receiving treatment twice, thrice or four times daily [5011 patients, RR=1.22 (95% CI, 1.11, 1.34]. Adults receiving an antibiotic once-daily were more compliant than those receiving the same antibiotic multiple times daily [380 patients, RR=1.09 (95% CI, 1.02, 1.16)]. Likewise, children that received an antibiotic twice-daily were more compliant than those receiving the same antibiotic thrice-daily [2118 patients, RR=1.10 (95% CI, 1.02, 1.19)]. Higher compliance was also found among patients receiving an antibiotic once compared to those receiving an antibiotic of different class thrice or four times daily [395 patients, RR=1.20 (95% CI, 1.12, 1.28)]. The finding of better compliance with lower frequency daily was consistent regardless of the study design, and treatment duration.

Conclusion

This meta-analysis showed that compliance to antibiotic treatment might be associated with higher when an antibiotic is administered once than multiple times daily for the treatment of specific infections and for specific classes of antibiotics.

Patients enrolled in randomised clinical trials are not representative of critically ill patients in clinical practice: observational study focus on tigecycline

It is being increasingly recognised by clinicians and scientists that participants in randomised clinical trials (RCTs) of antibiotics of last resort do not represent the patients who will later be treated with these drugs. Data on this subject are limited and have not been investigated systematically. This observational study aimed to examine this hypothesis quantitatively, using the example of tigecycline. To evaluate the influence of recruitment, patients eligible for clinical trials were retrospectively compared with ineligible patients regarding baseline and clinical characteristics as well as outcome parameters, e.g. length of hospital stay, intensive care unit (ICU) stay, ventilation and mortality. The clinical characteristics of 187 patients illustrated differences in the nature and severity of disease, co-morbidities and outcome. Eligible and ineligible patients differed in a number of parameters, e.g. median APACHE II score (15.5 vs. 28.0), number of liver transplantations (5% vs. 18%; P=0.048), septic shock (21% vs. 49%; P=0.001), need for mechanical ventilation (30% vs. 79%; P<0.001), mean length of ICU stay (19.3 days vs. 40.7 days) and death (19% vs. 46%; P=0.001). Critically ill patients were under-represented in clinical trials. Moreover, only a minority of patients in clinical practice (13%) were potentially eligible for a pivotal RCT. The disparities likely result from strict exclusion criteria in RCTs and recruitment bias. These data emphasise the importance of including critically ill patients in RCTs of antibiotics against multiresistant bacteria in order to account for those who will later be treated.

Effectiveness and safety of daptomycin in complicated skin and soft-tissue infections and bacteraemia in clinical practice: results of a large non-interventional study

This retrospective analysis of patients from eight countries included in the European Cubicin(®) Outcomes Registry and Experience (EU-CORE(SM)) captures the first post-approval years of clinical experience with daptomycin in its licensed indications. Of the total 1127 patients enrolled in EU-CORE between 2006 and 2008, 373 had a primary complicated skin and soft-tissue infection (cSSTI), most commonly surgical-site infection (48%), and 244 had bacteraemia, 55% of which were catheter-related. The most common pathogens were Staphylococcus aureus in cSSTIs (43%) and coagulase-negative staphylococci in bacteraemia (36%). The most frequently prescribed daptomycin doses were 4 mg/kg and 6 mg/kg for cSSTIs, and 6 mg/kg for bacteraemia. The median duration of inpatient and outpatient treatment, respectively, was 13 days and 8 days for cSSTIs and 8 days and 10 days for bacteraemia. Clinical success was reported for 81% of patients with cSSTIs and 77% with bacteraemia, with 82% success overall for infections caused by S. aureus. A trend towards higher clinical success was noted with higher daptomycin doses in bacteraemia (78% for 6 mg/kg vs. 90% for doses >6 mg/kg). Daptomycin demonstrated a favourable safety profile. Adverse events regardless of relationship to study drug were reported for 11% of patients with cSSTIs and 24% with bacteraemia, most commonly septic shock [7 patients (2%) with cSSTIs and 5 patients (2%) with bacteraemia]. These results demonstrate that daptomycin is effective and well tolerated in the treatment of cSSTIs and bacteraemia caused by Gram-positive bacteria in clinical practice.

Centre selection for clinical trials and the generalisability of results: a mixed methods study

BACKGROUND

The rationale for centre selection in randomised controlled trials (RCTs) is often unclear but may have important implications for the generalisability of trial results. The aims of this study were to evaluate the factors which currently influence centre selection in RCTs and consider how generalisability considerations inform current and optimal practice.

METHODS AND FINDINGS

Mixed methods approach consisting of a systematic review and meta-summary of centre selection criteria reported in RCT protocols funded by the UK National Institute of Health Research (NIHR) initiated between January 2005-January 2012; and an online survey on the topic of current and optimal centre selection, distributed to professionals in the 48 UK Clinical Trials Units and 10 NIHR Research Design Services. The survey design was informed by the systematic review and by two focus groups conducted with trialists at the Birmingham Centre for Clinical Trials. 129 trial protocols were included in the systematic review, with a total target sample size in excess of 317,000 participants. The meta-summary identified 53 unique centre selection criteria. 78 protocols (60%) provided at least one criterion for centre selection, but only 31 (24%) protocols explicitly acknowledged generalisability. This is consistent with the survey findings (n = 70), where less than a third of participants reported generalisability as a key driver of centre selection in current practice. This contrasts with trialists' views on optimal practice, where generalisability in terms of clinical practice, population characteristics and economic results were prime considerations for 60% (n = 42), 57% (n = 40) and 46% (n = 32) of respondents, respectively.

CONCLUSIONS

Centres are rarely enrolled in RCTs with an explicit view to external validity, although trialists acknowledge that incorporating generalisability in centre selection should ideally be more prominent. There is a need to operationalize 'generalisability' and incorporate it at the design stage of RCTs so that results are readily transferable to 'real world' practice.

Clinical experience with daptomycin in Europe: the first 2.5 years

Objectives

To describe the patient populations and infections being treated with daptomycin, as well as the efficacy and safety outcomes.

Patients and methods

Data from the European Cubicin Outcomes Registry and Experience (EU-CORE^SM), retrospectively collected at 118 institutions between January 2006 and August 2008, were analysed.

Results

Daptomycin treatment was documented in 1127 patients with diverse infections, including complicated skin and soft tissue infections (33%), bacteraemia (22%), endocarditis (12%) and osteomyelitis (6%). It was used empirically, before microbiological results became available, in 53% of patients. Staphylococcus aureus was the most common pathogen (34%), with 52% of isolates resistant to methicillin; coagulase-negative staphylococci and enterococci were also frequent, with 22% of Enterococcus faecium isolates resistant to vancomycin. Daptomycin was used as first-line therapy in 302 (27%) patients. When used second line, the most common reasons for discontinuation of previous antibiotic were treatment failure and toxicity or intolerance. The use of concomitant antibiotics was reported in 65% of patients. Most frequent doses were 6 mg/kg (47%) and 4 mg/kg (32%). The median duration of daptomycin therapy was 10 days (range 1–246 days) in the inpatient setting and 13 days (range 2–189 days) in the outpatient setting. The overall clinical success rate was 79%, with a clinical failure rate of <10% for all infection types. Low failure rates were observed in first- and second-line therapy (6% and 8%, respectively). Daptomycin demonstrated a favourable safety and tolerability profile regardless of treatment duration.

Conclusions

Daptomycin has a relevant role in the treatment of Gram-positive infections.